1. Field of the Invention
This invention relates generally to a method of determining the parts packaging sequence, and more particularly to a method of determining the packaging sequence of an automatic packaging machine so as to mount parts, which have a constraint concerning the packing sequence, on a substrate in a short packaging time.
2. Description of the Related Art
A packaging machine includes an XY table turning inserter, an XY head turning inserter, a one-by-one sequence mounter, and XY table type one-by-one random access mounter, an XY head type one-by-one random access mounter shown in FIGS. 16, 17, 18, 19 and 20, respectively. FIGS. 8(a) through 8(e) are expanded figures of parts supply portion, table, etc. of these machines. FIG. 8(a) is the XY table turning inserter; (b), the Xy head turning inserter; (c), the one-by-one sequence mounter; (d) and the XY table type one-by-one random access mounter.
When creating NC data for a packaging machine, it is necessary to determine the packaging sequence.
FIGS. 10 through 12 of the accompanying drawings show conventional methods.
The method of FIG. 10 is a one-point search method. In this method, when mounting parts on a substrate 101, the packaging sequence of all parts is determined by sequentially selecting the part nearest to the part that has been mounted (or the part whose standby time for movement in the XY direction is shortest or the part whose standby time for supply is shortest or the part whose standby time for the turn of an XY table is shortest).
The method of FIGS. 11(a) and 11(b) is a method to be used in a packaging machine having a rotary index (not shown). After a part b has been mounted, a part that can complete both the movement of an XY table (not shown) carrying a substrate 112 and the movement of a parts supply portion 111 is selected to be mounted next while the rotary index turns for a single part.
FIG. 11(a) shows the range of the parts supply portion 111 within which a part next to the part b can be mounted, and FIG. 11(b) shows the range of the substrate 112 within which a part next to the part b can be mounted.
In this condition, if there is no part that can be selected next, the condition is softened to determine the packaging sequence of all parts.
FIG. 12 shows a packaging sequence in which parts are arranged orderly like IC parts.
The substrate 121 is divided into regions in the X direction (or the Y direction), and parts c within each region are sequenced in ascending or descending order of the Y coordinate (or the X coordinate); thus the packaging sequence for all parts in all regions are determined. This prior art is exemplified by Japanese Patent Laid-Open Publication No. SHO 63-204301.
A one-point search method is used when the packaging sequence is determined in the XY table turning inserter, the XY head turning inserter, the one-by-one sequence mounter, and the XY table type one-by-one random access mounter. In the above mentioned packaging machines, a substrate is placed on an XY table to change the mounting position of the parts by movement of the XY table. In this case, packaging the parts in succession which are located nearby the parts being mounted, would reduce the amount of movement of the table, resulting in completing the packaging in a short time. In the one-point search method, however, there is a case in which some parts that are located relatively nearby the parts being mounted, would not be the nearest parts and would be left behind to the last, like the part A in FIG. 10, thereby the amount of movement of the table is increased as a whole.
The method of determining the packaging sequence shown in FIG. 11 cannot be adopted to the XY table turning inserter, the XY head turning inserter, or the XY head type one-by-one random access mounter because this method can be adopted only to a packaging machine having a rotary index. Further, also in the packaging machine having the rotary index such as the one-by-one sequence mounter, the XY table type one-by-one random access mounter, there is a problem that a constraint with respect to the turning speed of the rotary index itself is not considered in the method shown in FIG. 11.
This problem that the constraint with respect to the turning speed of the rotary index itself is not considered, is caused by the following reasons. The rotary index, in most cases, is capable of controlling the turning speed. If the mounting part, which are the parts to be drawn by the nozzle of the rotary index, is easy to be picked and hard to be dropped down during the turn at a high speed, then the constraint that packaging can be carried out at high speed is established. On the other hand, if the part is easy to fall down, then the constraint that packaging should be carried out at a low-speed turn and the part which can bear a high-speed turn, are simultaneously drawn by the rotary index, it is necessary to adjust the turning speed to the low-speed turning part. Therefore, it is not desirable to take a plurality of parts which require different turning speeds, because it makes the packaging time longer.
The method of determining the packaging sequence by dividing into regions as shown in FIG. 12, can be employed in the XY table turning inserter, the XY head turning inserter, the one-by-one sequence mounter and the XY table type one-by-one random access mounter. However, adopting this method to a substrate on which parts are not arranged orderly, would be a large loss in movement of the substrate. This problem is caused by the reason similar to that of the one-point search method described above. Further, when determining the packaging sequence, it would be necessary to satisfy a constraint concerning the packaging sequence.
This constraint may be such that a determined packaging sequence should be carried out with out damaging any other part when each part is mounted.
Consequently, a packaging sequence should be determined to satisfy a constraint such that each part does not damage any other part. Further, conventional systems are disclosed in "Automatic Components Insertion/Placement Systems Ready for the Automatic Factory" by H. W. Markstein, Electronic Packaging and Production, pp. 106-112, August 1984. Markstein discloses an example of a packaging machine as illustrated in FIG. 8 of the present application. However, Markstein suffers from the same disadvantages shown above with respect to Japanese Patent Laid-Open Publication No. SHO 63-204301.
Further conventional systems are disclosed in U.S. Pat. Nos. 4,293,998; 4,342,090; 4,539,740 and 4,969,256. Each of these references discloses a structure for an automatic inserter device particularly as it relates to a parts supply structure, a position determining mechanism and an automatic inserter for axial parts. However, these references suffer from the disadvantages described above being that they do not address the problems associated with the packaging sequence.
Other conventional systems are disclosed in U.S. Pat. Nos. 4,980,970; 5,083,281; 5,086,559 and 4,630,428.
U.S. Pat. Nos. 4,980,970; 5,083,281; and 5,086,559 each discloses automatic insertion and placing apparatus. However, these conventional systems suffer from the disadvantages described above being that they do not attempt to optimize the speed of packaging by determining the packaging sequence of the parts. U.S. Pat. No. 4,630,428 suffers from the disadvantage of not adjusting the packaging sequence depending on the positional relationship between the packaging machine and the parts.
None of the foregoing conventional methods, however, considered any constraint concerning the packaging sequence.